How to Make a Backyard Fish Pond from Scratch

Adding a free-formed fish pond or other similar water feature to your backyard is a superlative landscaping idea that may be accomplished with moderate skills and tools. Not only do the ponds look great, if stocked right they may also help to control some common insects. Sound interesting? Here’s what you need to know to make a six foot by 4 foot by 2 foot fish pond of your own.

Materials Needed to Create a Backyard Fish Pond

In order to make a backyard fish pond from scratch you will need to gather together the following materials;

1 bag (6 ½) with minimum slump (yield: 3/5 cubic yards of concrete)
350 gallons of water
1 long garden hose
1 wheel barrel
1 heavy duty spade
1 rubber mallet
1 pair work gloves
1 pair safety goggles
1 pair scissors
1 pair wire snips
1 car tire
1 roll plastic or old shower curtain
1 roll black plastic sheeting
1 roll wire reinforcing mesh, 6 inches by 6 inches (approx. 12 feet long)
12 rocks, 2 inches high
1 shovel
8 wooden 2 inch by 2 inch stakes, 10 inches long
1 pencil
1 metal tape measure
1 board, 2 inches by 12 inches
1 metal coffee can, 2 pound size with ends removed and cut in half
1 pointed trowel
1 square trowel
1 level
1 wood float
1 roll wire mesh screen, 1 inch by 1 inch (for runoff channel)
1 old cloth blanket, king size

Step 1: Excavating the Pond

Every homemade, backyard fish pond project starts with the excavation of the hole. Before starting to dig the hole, there are some important caveats that must be discussed. For this project the hole’s slopes must be no more than 70 degrees. Failure to keep the slopes 70 degrees or less will cause disastrous problems during the concrete pouring phase. This is because an improper slope tends to cause the concrete to run off the sides and pool into the center of the hole, leaving you with a big ball of concrete instead of a beautiful, backyard fish pond. In addition to the sloping requirements, the hole should have a depth of 28 inches, be six feet long by four feet wide with an extra allowance of four inches on all sides. A good way to mark out your excavation area is to use a spade to score the hole’s entire rim.

Step 2: Preparing the Pond for Pouring

Because this fish pond design is employing a free-form design the hole is not conducive to an ordinary tamper. This is where the car tire comes in. Use the car tire as your tamper by bouncing and rolling it inside and around the perimeter of the excavated hole until the dirt is well compacted. Once the dirt is properly tamped you may turn your attention towards creating the fish pond’s wire form.

To create the wire form you will need at least a 12 foot piece of 6 inch by 6 inch wire mesh, 1 roll of black plastic sheeting, wire snips, tape measure, a pencil and rocks. Bend and cut the wire into a bowl shape that matches the hole you excavated in step one. It is imperative to note that the wire form should reach close to the outer rim of the hole. After the wire form has been created, you will need to temporarily set it aside while you create the form’s base.

To create the form’s base, measure and cut a piece of black plastic sheeting that completely covers the hole’s edge and extends one foot down the sloped sides. Proceed by taking two inch tall rocks and placing them inside the hole at one foot intervals. The rocks are going to serve as the wire form’s support system so it is imperative that the rocks are as level and sturdy as possible. Once the rocks are in place, lower the wire form into the hole and rest it on top of the rocks. It is now time to create your concrete depth markers.

Remember that it is important that the center depth of the fish pond is four feet deep. This can be hard to maintain without the aid of depth markers. To create depth markers you will need 10 inch long wooden stakes, a mallet, a pencil and a tape measure. Starting at the hole’s edge, measure and mark off one foot intervals between the openings in the mesh. These one foot intervals will serve as insertion points for the wooden stakes. Use the mallet to hammer one stake at every insertion point. Once the stakes are in the ground, take your tape measure and pencil. You will want to measure each stake from the ground up, making a hash mark with your pencil at the four inch mark. The pencil marks will serve as your depth guide during the pouring process, so be sure to make them dark enough to be visible from a distance.

Step 3: Preparing and Pouring the Concrete

After the hole has been properly prepared it is time to prepare and pour the concrete. Prepare the concrete according to the manufacturer’s instructions. Keep in mind that the concrete should have a minimum slump of 4 inches. The reason being is that your concrete should be stiff but reasonably malleable. Concrete with less than a four inch slump would be too stiff and more than 6 inches of slump would be too runny. In addition, if you live in an area where freezing, winter temperatures are common you will want to purchase concrete that contains coarse, aggregate gravel that has a maximum diameter of one inch with 6% air entrainment. Those living in areas with mild winters must also request a concrete mixture that contains coarse, aggregate gravel that has a maximum diameter of one inch but may opt to use concrete with a 4% air entrainment. The size of the gravel and the air entrainment level is important because you will be pouring the concrete in thin layers. The wrong size gravel and air entrainment levels may cause the finished product to crack and there is nothing worse than a fish pond that leaks. If you are still unsure about what ready-mix concrete you will need for your area, consult with your local mason or building code professional.

Once your concrete has been prepared, it is time to pour. Place a wooden board across the width of the hole. It will serve as a place where you may stand while shaping the concrete. Slowly pour the concrete into the hole so as not to disturb the wire form. If the wire form does get disturbed in the process, you will need to quickly reset it back into position. It is important that the wire form does not sink below the 2 inch level of the rocks and that you fill the hole up to the four inch depth mark on the wooden stakes. Once you reach the four inch depth mark, you will need to remove the stakes so that they do not become a permanent part of the finished fish pond.

You will also need to put a ring of concrete onto the black plastic sheeting that rims the hole. This is where you will be creating the fish pond’s edge and run off channel. Before attempting to create the fish pond’s edge and run off channel, smooth the inside of the pond’s bowl with a wood float. Once the pond’s bowl is smooth, it is time to turn your attention to creating the pond’s edge.

To create the fish pond’s edge you will need your modified, metal coffee can and a pointed trowel. Similar to the concept of making a sand castle, use the modified coffee can and pointed trowel to form the concrete sitting on the black plastic sheeting into a half cylindrical shaped rim. After the rim has been created, you may turn your attention towards creating the fish pond’s run off channel.

To create the run off channel you will need your tape measure, coffee can, pointed trowel, wire snips and a four inch piece of one inch by one inch wire mesh. Cut the mesh to size and temporarily set it aside. The mesh is designed to allow excess water to run out of the fish pond while keeping the fish from running out along with the water. Use the coffee can and trowel to remove a 3 inch wide, semi-circular section of the pond’s rim. Insert the wire mesh securely into the semi-circular hole. You will want to make sure that there are no sharp edges poking out that could hurt the fish or anything else for that matter. That is all there is to making a run off channel.

Step 4: Putting the Finishing Touches onto Your Backyard Fish Pond

With the pond poured and shaped you will want to cover the pond with plastic and monitor the concrete’s surface after one hour. If after one hour the concrete’s surface is free of water, use a square trowel to re-smooth the pond’s surface. Once done, recover the pond and repeat the procedure two more times until you can touch the concrete’s surface without leaving an impression. The repetitive covering and re-troweling is necessary to keep hairline cracks from forming in the concrete as it cures.

After the third trowel you will need to take out an old blanket and wet it with your garden hose. The fabric should be damp but not sopping wet. Place the wet blanket inside the pond’s bowl area. The wet blanket should continue to cover the pond’s bowl until the concrete has completely cured. Note that depending on how long the concrete takes to cure, you may have to periodically re-wet the blanket. From personal experience, it often takes three or more days for the concrete to completely cure.

Once the concrete has cured, cut away any excess black sheeting from the pond’s rim. Fill the pond with roughly 350 gallons of water, gold fish and aquatic plants as desired. Please note that an aerator is generally not needed for such a shallow fish pond, but you may add one if it makes you feel more comfortable.

Suggestions on Stocking Your Backyard Pond

As previously mentioned, certain flora and fauna may help to control common backyard pests like mosquitoes. Gold fish, catfish, frogs and snails are helpful in that regard as are certain aquatic grasses and plants. For the best flora and fauna to use in and around your backyard pond, consult with your local gardening or landscaping expert.